1. Field of the Invention
The present invention relates to a pressure plate subassembly for a motor vehicle friction clutch with automatic wear compensation. The pressure plate subassembly includes a housing, which is connectable to a flywheel for joint rotation about an axis of rotation, a pressure plate, arranged in a rotationally fixed and axially displaceable manner in the housing, a force accumulator supported on one side on the housing and on the other side on the pressure plate for pressing the pressure plate toward a side of the housing that is connectable to the flywheel, a wear readjusting device arranged in the support path of the force store having at least one readjusting element that is displaceable for wear compensation and is preferably biased toward a wear-readjusting direction, and at least one clearance transmitter arrangement to register wear of friction linings of a clutch disk of the friction clutch that can be clamped or is clamped between the pressure plate and the flywheel, wherein the clearance transmitter has a readjusting arrangement to cooperate with the wear readjusting device.
2. Description of the Related Art
A prior art pressure plate subassembly of this type is known, for example from reference DE 43 06 688 A1. In this known pressure plate subassembly, an axial bore is provided in the pressure plate for a clearance transmitter which passes through said axial bore with a wear registering section with movement clearance. The wear registering section has a first end and a second end. The first end of the wear registering section is designed to engage on a flywheel and the second end of the wear registering section is fitted with a lever section. The clearance transmitter cooperates with a wear readjusting device for the compensation of wear occurring during operation of the friction clutch. The clearance transmitter is tilted in the axial bore by a spring, and is thus pressed into a frictional clamping seat in this bore. An axial loading of the lever section cooperating with the readjusting device as a result of the readjusting device being biased in the wear readjusting direction does not lead to the clearance transmitter being axially displaced by the readjusting device. Thus an undesired axial expansion of the wear readjusting device is not produced.
The pressure plate is displaced toward the flywheel when wear occurs during operation because of the reduction in thickness of the clutch disk. In so doing, the wear registering section abuts the flywheel and is thereby displaced by the spring in the axial bore counter to the biasing action, so that during a subsequent disengaging operation the wear readjusting device can expand axially until it abuts the lever section once more.
A problem with this known pressure plate sub-assembly is that the clearance transmitter is severely influenced by centrifugal force, with the result that the displacement characteristic or the operating characteristic may change with the centrifugal force so that the operating characteristics of the clearance transmitter is dependent upon the rotational speed of the engine.